Human immunodeficiency virus type 1 (HIV-1) remains one of the leading causes of death worldwide, principally in developing countries. Although therapeutic agents exist for the treatment of HIV-AIDS, drug-induced toxicities and pharmacokinetic limitations commonly result in poor compliance and disease related complications such as, for example, HIV-associated neurocognitive disorders (HAND).2,4 HAND is one of the most common manifestations of HIV-1 pathogenesis that causes cognitive impairment and other CNS-related disorders.5-9 
Even with the advent of combination antiretroviral therapy (cART), over 40% of HIV-1 infected patients experience neurological complications.9 Moreover, rates of HAND are likely to rise in the coming years as anti-HIV-therapies continue to extend the lifespan of patients.
Major limitations of cART include, but are not limited to, complex dosing regimens, drug metabolism, and limited penetration into viral reservoir organs such as the CNS and the lymphoid tissues.1,2 
For treating disorders such as HAND, delivery of therapeutic agents to the CNS remains a major challenge, primarily due to the ineffective transmigration of drugs through the blood-brain barrier (BBB).
In recent years, the advent of nanomedicine has stimulated the development of innovative systems for drug delivery. However, clinical success has been limited due to problems associated with biocompatibility, sustainability, and cytotoxicity of the drugs.
Nanodiamond (ND) is known to be a non-toxic, biocompatible, and chemically inert material when used under typical biological conditions. ND, being crystalline carbon particles with sizes on the order of nanometers (e.g. less than 10 nm), have demonstrated a unique ability to accommodate surface modifications. This is due to their surface activity and large surface area with respect to volume.